Depression and binge eating disorder were common among bariatric surgery patients, according to a meta-analysis.

Based on an analysis of data from 68 studies -- 59 studies reporting on preoperative mental health conditions; 27 reporting on how those conditions related to postoperative outcomes -- the most common mental health condition was depression, with a 19% prevalence (95% CI 14%-25%), followed by binge eating disorder (17% prevalence, 95% CI 13%-21%), reported Aaron Dawes, MD, of the David Geffen School of Medicine at the University of California Los Angeles, and colleagues.

However, there was conflicting evidence for an association between preoperative mental health conditions and weight loss after the surgery, they wrote in the Journal of the American Medical Association.

"Though no one should be prescribing bariatric surgery to treat depression, the findings help physicians better understand candidates for surgery and mental health factors to consider when treating these patients," Dawes wrote in an email to MedPage Today.

In 11 of 12 studies looking at depression, the condition improved after bariatric surgery. Both prevalence and frequency and severity of reported depression symptoms were found, they noted.

The authors looked at prevalence of other mental health conditions as well, including anxiety, post-traumatic stress disorder (PTSD), substance abuse disorders, suicidality, or suicidal ideation. They did not look at nondisordered eating behaviors and smoking.



Weight loss was used as the postoperative bariatric outcome. To be included in the analysis, each study had to report findings from primary research and report on outcomes for adults with a body mass index (BMI) of at least 35 kg/m2. Diagnosis of mental health conditions was done prior to surgery in all of the studies. The studies were classified based on their quality, from very low quality to high quality.

The most commonly studied conditions was depression (analyzed in 34 studies), followed by binge eating disorder (25 studies) and anxiety (22 studies). The majority of the patients were women (70%-80%) with a mean age of 40-50. The mean BMI was 45-50 kg/m2 .

Nearly a quarter (23%) of patients had at least on mood disorder (95% CI 15%-31%) compared with the estimated 10% in the general population, while 12% had anxiety (95% CI 6%-20%). The authors also gave estimates for prevalence of suicidal ideation (9%, 95% CI 5%013%), substance abuse disorders (3%, 95% CI 1%-4%), and PTSD (1%, 95% CI 1%-2%).

Only depression and binge eating disorders were higher in the patient population than in the general U.S. population (8% for depression, and 1%-5% for binge eating disorder), according to the authors.

Five studies looked at preoperative depression and postoperative weight loss. One of those studies found that there was no relation at 1 year after surgery, but at 4 years they had weight loss. The other four studies found no such relationship. Results were similarly mixed for binge eating disorder and postoperative outcomes.

"The quality of evidence was very low for all associations between preoperative mental health conditions and postoperative weight loss," the authors wrote, adding that depression was the exception, where the evidence was categorized as 'low.'

Evidence surrounding bariatric surgery and alcohol use was mixed: three studies found no relationship between alcohol use disorder and laparoscopic adjustable gastric band surgery, but one of those studies also looked at Roux-en-Y gastric bypass and found that those patients were more likely to have higher alcohol abuse rates than others.

"The quality of evidence was moderate that bariatric surgery is associated with lower postoperative rates of depression, fewer symptoms of depression, and decreased usage of antidepressant therapies, at least during the first 3 years after surgery," they stated.

Finally, they did note that two randomized controlled trials, which evaluated behavioral health interventions after bariatric surgery, found improvements in depression for both the intervention group and the usual-care group.

Study limitations included the fact that the various papers used scales, thresholds, and definitions differently; binge eating disorder, for example, was redefined in 2013 with the release of a new diagnostic manual. The analysis also did not address the severity of mental health conditions. Bariatric surgery candidates with severe mental illness are often screened out prior to receiving surgery so weren't included in the analysis.

In addition, the authors included single-site studies only, a factor that could have limited generalizability and bias the findings. "Future work can help to identify the optimal strategy for evaluating patients' mental health prior to bariatric surgery," they stated.

"I have found in my large experience spanning over many years and thousands of patients that depression is indeed found often in this population," wrote Namir Katkhouda MD, of the Keck School of Medicine at the University of Southern California in Los Angeles, in an email to MedPage Today.

Richard Stahl, MD, of the University of Alabama at Birmingham, pointed out that the finding that bariatric patients had a greater prevalence for depression and binge eating versus the general population also was important. The study authors agreed, stating that "special attention should be paid to these conditions among bariatric patients."

Guidelines from the American Society of Metabolic and Bariatric Surgery and from the Department of Veterans Affairs recommend assessment of patients' mental health conditions. Other groups push for comprehensive mental health examinations. But the authors wrote that, "the results of our study do not defend or rebut such a recommendation."